01 -
In a small bowl, combine mayonnaise, ketchup, mustard, pickle relish, garlic powder, onion powder, and a pinch of salt. Mix thoroughly and refrigerate until ready for use.
02 -
Melt 2 tablespoons of butter in a skillet over medium heat. Add the sliced onions and cook, stirring frequently, until deeply golden and softened, about 15 minutes. Transfer to a bowl and set aside.
03 -
In a large bowl, combine ground beef with salt, black pepper, garlic powder, onion powder, and Worcestershire sauce. Gently mix until incorporated. Divide mixture into 4 equal portions and form into thin, wide patties slightly larger than the bread slices.
04 -
Heat a large skillet or griddle over medium-high heat and coat lightly with cooking spray or oil. Sear each beef patty for 3 to 4 minutes per side until browned and cooked through. Set aside on a plate.
05 -
Arrange 8 slices of rye bread on a clean surface. Spread signature sauce onto 4 slices. On each sauced slice, place 1 slice of cheese, a cooked patty, caramelized onions, another slice of cheese, and top with a plain bread slice.
06 -
Melt 2 tablespoons butter in a clean skillet over medium heat. Place each sandwich in the pan and cook for 3 to 4 minutes per side, pressing lightly with a spatula, until bread is crisp and golden brown and cheese is melted.
07 -
Cut each sandwich in half and serve hot with extra signature sauce on the side for dipping.